Secondary explosion:Myth or reality?

 Since the discovery of Britannic's wreck in 1975, many people (from simple divers to famous scientists) dived into the waters near the island of Kea. However, none of them was able to lift the veil of mystery regarding the cause of the explosion that led to the sinking of the white titan. It seems that the possibilities are two: mine or torpedo. The great dimensions of the hole in the hull was an indication that the hit may have caused a secondary massive explosion the origins of which would be even more obscure, as Britannic's cargo manifest is lost. Over the years some researchers explored this possibility and proposed various causes that could have led to a secondary explosion but the findings of the diving expeditions gave good evidence against this theory.


Coal dust

As the ship was close to destination much of the coal in the holds had been consumed, but the coal dust, highly explosive, remained in the air. A violent shaking of the vessel combined with fire could easily  trigger an explosion in the reserve coalbunker located near the area of the hit. The answer came from the divers of the 1999 expedition who discovered that the reserve coalbunker was actually intact.


Ether stored in the cargo holds

As a hospital ship, the Britannic was carrying large quantities of medical equipment, surely including ether. This chemical is a gas largely used as an anesthetic during that period but also highly flammable. The holds were found empty, so there is no way to be certain about the cargo they contained that day.


Illegally transported arms

  The divers found absolutely no trace of arms.

 Dr. Robert Ballard ,who examined in detail the wreck in 1995, suggested that the extension of the hull damage was the result of the bending of the bow against the seabed during the sinking. Britannic sank in relatively shallow waters and  hit the seabed before she was totally submerged and the bow section was almost detached from the rest of the hull. Another point against the secondary explosion theory comes from the official inquiry, completed on November 24,1916 aboard the flagship HMS Duncan at Pireaus, by H. H. Heard (Captain) and G. H. Staer (Engineer Commander). The inquiry clearly states thatthere was only one explosion.


The big question: Mine or torpedo?

 It's generally accepted that Britannic sank after striking a mine, mainly thanks to the conclusion of the official inquiry: "The effects of the explosion might have been due to either a mine or a torpedo; the probability seems to be a mine". Unlike the secondary explosion issue, in this case the official inquiry makes things very complex, because it also reports a series of evidence which strongly support the torpedo theory. The reasons for this controversy were the lack of time at disposal  and the inability to locate the witnesses, as the survivors had been already transferred to various ships along the fleet. Many other sources also give evidence in support of the torpedo theory.

 Attacking hospital ships was forbidden by international laws but during WW1 there were some cases when over-zealous German U-boat captains ignored them openly, especially during the last years of the conflict. The escalation of those attacks culminated with the tragic loss of HMHS Llandovery Castle on June 27,1918 by U-86. The ship, used by the Canadian Army Medical Corps (CAMC), was torpedoed without warning. Despite the list, some lifeboats were lowered with success and began collecting survivors from the water but  the lifeboat with the nurses was drawn into the whirlpool formed during the sinking of the ship.U-86 surfaced and its crew ordered the men on the lifeboats to stop helping those on the water. After a brief discussion alongside the submarine, where officers of the CAMC were accused of being American flying officers, the submarine tried to ram the lifeboats and then opened fire against the survivors.In total, 146 people lost their lives (almost the entire medical personnel).

The loss of the Llandovery Castleused for promoting war bonds in a 1918 poster.


The torpedo theory

 Before presenting the evidence, it would be useful to bring to your attention some information regarding torpedoes. The torpedoes used in WW1 were ejected using compressed air. That air didn't remain into the submarine, so the launch was followed by a big bubble of air (the "wake" of the torpedo) on the surface. During its course, the torpedo was also leaving a visible trail of bubbles behind it. So it's not surprising that a rapid vessel could escape being hit if those signs were detected early enough.


This is a fine example of how a WW1 torpedo track looked like. It would be clearly visible from Britannic's decks.


a) Arguments supporting the torpedo theory:


bulletThe official inquiry:

 At least three witnesses gave "good evidence" of having seen:

- a periscope

-the wake of a torpedo and its direction -the torpedo track- just before the explosion. This statement was given by steward P. Walters who had seen torpedo practice before while serving in the Royal Navy. He even clutched the rails waiting for the explosion. However, he didn't claim to have seen the torpedo itself (Walters saw the torpedo track on the port side).

-the wake of a torpedo on the port side missing aft

  There's also the testimony of baker H. Etches who claimed to have seen a torpedo track further aft but on the starboard side. This statement at first glance is controversial, but if the second torpedo (launched from the port side) had missed the rudder, its track could be visible from the starboard side too.

 The official inquiry also notices that the sea was "glassy smooth", which means that it would be quite easy to spot a torpedo track.

bulletRev. John Fleming's account:

 In his book The Last Voyage Of HMHS Britannic, Rev. John Fleming reports that "...Numbers of the ship's people agree that they saw what they took to be a torpedo miss the rudder, and a second one find us in the bow...".In addition, he reports that the Greek villagers had seen a submarine going out early that same morning, just hours before the passage of the Britannic.

bulletGerman newspaper article + German intelligence reports:

 In his book The Olympic-Class Ships Mark Chirnside offers the following quote from the German newspaper Kieler Zeitung (Note: I've also found this quote in a  booklet published in 1917 and titled The War On Hospital Ships):

"The Britannic was transporting fresh troops for our enemies. If she had not been doing so, our submarines would never, of course, have torpedoed her"

 Such an open admission of the torpedoing of a hospital ship is absurd, however it seems that the above quote was part of an official statement and if it was published after the war (not known) it may have some validity.

In addition, in a statement issued by the British Admiralty on December 3, 1916 we read:

"...German wireless messages to the Embassy, Washington, are again promulgating mendacious reports, purporting to come from Rotterdam, that the hospital ship "Britannic", recently sunk, had troops on board...".[Source: The War On Hospital Ships (1917)]

 If the Germans were convinced that the Britannic was carrying troops or ammunitions they wouldn't hesitate to torpedo her.

bulletCaptain McNeal's account:

 Another find by Mark Chirnside is the following quote:

"The Warren telegraphist reported to me that he had picked up a disconnected message, stating that a German submarine had wirelessed to friends in Athens announcing his intention of torpedoing the largest ship in the world [afloat] ,the Hospital Ship Britannic, because she was known to be carrying troops. At the same time I was aware that the Germans were capable of sinking anything without an excuse"

[Source: Titanic Commutator, Britannic special (Winter 1978)]


bulletOfficial statement of the British Admiralty:

 On April 17,1917 ,after the loss of HMHS Donegal and HMHS Lanfranc, the Admiralty decided to make a summary of  the attacks on hospital ships. A quite long statement was issued presenting the evidence case by case. The concluding paragraph stated the following:

"In the light of the recent events it seems reasonable to suppose that the hospital ships Braemar Castle and Britannic were also torpedoed in Nov.1916,although the evidence at the time was not considered conclusive as to whether their loses were occasioned by mines or torpedo"

[Source: The War On Hospital Ships (1917)]


bulletArticle from The Times :

 Mark Chirnside also found this quote from "The Times":

"[...] two submarines were lying in wait by the island of Kea with the express object of sending the Britannic to the bottom. She was attacked from both sides at once,* each of the submarines launching a torpedo against her. One of them missed its mark, the other inflicted a fatal blow on the ship."

* This could explain the two conflicting testimonies of the official inquiry.


bulletStoker Bert Smith's account

Mark Chirnside has recently found the account of Mr. Bert Smith, who was a stoker on the Britannic.

 Shortly before the explosion, Smith had passed from the firemen's tunnel and had started to work in Boiler room No.6. Then "..there was a very loud bang. Almost instantly this was followed by a massive explosion - just in front of number one stokehold, where Bert was on duty. Shocked and covered in coal dust, Bert Smith groped his way into the exit tunnel, his one route to possible safety. There he was met by the full weight of inrushing water, which briefly pinned him against the boiler...". Smith managed to escape using another stair.

 What makes his testimony more interesting, is the fact that he had survived from two different disasters in the past. He had been on the Galeka when she was mined, and on a Blue Funnel freighter named Moyune which was torpedoed. Knowing the different "feeling" between  the two explosions, he was convinced that the Britannic had been torpedoed. It's not easy to determine what this different "feeling" was. A personal impression based on something so vague may not be very objective and it shouldn't be used as hard evidence. However, it's one more indication that gives credit to the torpedo theory. In addition, it the first account that states clearly that there was a secondary explosion.


b) Arguments against the torpedo theory:


bulletThe official inquiry:

 The inquiry states that:"..there is no evidence of a column of water having been thrown up outside the ship...".This is a significant argument. In fact, this is a characteristic evidence of a torpedo hit.


The mine theory

 At this point it would be very useful to know what type of mines were using the Germans in the Kea Channel.

-Drifting mines: They were floating freely on the water. Their use seems improbable in this case, since it would be very dangerous for a submarine to surface and operate in a strait full of drifting mines.

-Moored mines: Used in deep water. The mine itself, was located in a negative-buoyancy case (that tended to float). A chain or cable, attached to an anchor on the seafloor, held the mine at a predetermined depth. This type of mine was  used in the Kea Channel.


Deployment of moored mines by submarine

(Courtesy Britannic 2003 Expedition)


a)Arguments supporting the mine theory:

 The  inquiry doesn't mention a single argument in favor of the mine theory. The only available written evidence we have is the account of a prisoner captured after the sinking of the German submarine UB109, who claimed that he was aboard the German mine-laying submarine U73 when it had laid mine barriers in the Kea channel less than an hour before Britannic's passage. After the war, the commander of U73 Gustav Siess confirmed that U73 was in the area that period and  its mines where responsible for the damage of another British  hospital ship and the sinking of a French steamer, a week before the sinking of the Britannic  [Source:Simon Mills-"Britannic, The Last Titan].


The U73 (National Maritime Museum)


Chart from U73's log showing the mine barrier laid just off the port of St. Nicolo on October 28, 1916. The actual location of the wreck is not far from this barrier (Titanic Historical Society Archives)

 The log of U73 does not supply much evidence but gives us an idea of the tactics used by German submarines. On October 28,1916 the submarine was in the Kea Channel. The submarine surfaced at day-break in order to lay the mines. It was observed that the enemy steamers (including hospital ships) were sailing along the Kea-side of the strait. This means that most probably the mines were usually laid closer to Kea, along Britannic's usual route. The submarine laid 2 barriers. Each barrier of mines consisted of 6 units. Later on, it took a waiting position north of the barrier, in order to torpedo steamers which would have passed without striking a mine. It's clear that the submarine sighted by the Greek villagers on November 21, could have laid a mine barrier (this would confirm the testimony of the German prisoner) but it may also have torpedoed Britannic just after the mine barrier.

Mine barrier (6 mines) laid on October 27, 1916.

Gulf of Athens (Saronikos)

Mine barrier (6 mines) laid on October 27, 1916.

Gulf of Athens (Saronikos)

Mine barrier (6 mines) laid on October 28, 1916.

Kea Channel

Mine barrier (6 mines) laid on October 28, 1916.

Kea Channel

Mine barrier (4 mines) laid on October 29, 1916.

Myconos Channel

Mine barrier (6 mines) laid on October 29, 1916.

Myconos Channel

click on image to enlarge

The images above were created using the co-ordinates provided by the log of U73 for the very successful patrol of  late October 1916. One can only admire the accurate positioning of the mine barriers exactly over the paths of the shipping lanes without the use of modern technology. This accurancy caused the sinking of the HMHS Britannic (Kea Channel on Nov.21), the serious damaging of the HMHS Braemar Castle (Myconos Channel on Nov.23) and the loss of two Greek steamers in the Gulf of Athens.


bulletRemains of mine barrier

 The 2003 diving expedition has located the remains of a mine barrier near the wreck. There was no available time in order to explore the site with divers but the sonar scans showed the presence of mine anchors and what it seems to be a broken mine casing. Take notice that the position of this mine barrier is very close to the position reported in the log of U73. Without any doubt this finding gives a huge boost to the mine theory and it looks certain that the area in question will be examined in the future.

Bill Smith shows the sonar image of a mine anchor (Courtesy of Bill Smith)

Sonar image of an egg-shaped "target" located near the mine anchors. It can be seen near the mouse pointer in this image. A broken mine casing? (Courtesy of Bill Smith)


b) Arguments against the mine theory:

bulletThe Official inquiry:

 Surprisingly, the inquiry offers an argument against the mine theory: "Water was deep, probably over 100 fathoms and there is a current through the Kea Channel. This against the mine theory".



 As you may have seen, the quest for the truth is quite difficult in this case. We may never find what really happened in the Aegean Sea that Tuesday of 1916. Britannic still holds the mystery of her demise well hidden inside her rusty wreck and despite the use of modern technology we haven't able to solve this enigma yet. Most indications (some weak, some strong) lead to a torpedo attack but the hardest evidence we have so far comes from the 2003 expedition and it is the discovery of a mine barrier near the wreck. The British Admiralty may have the reply, but some of the documents regarding the Britannic are still considered military secret and access to them is impossible. Perhaps it's better this way. Some ships are fascinating just because their fate is covered by a veil of mystery.


Many thanks to Mark Chirnside. His assistance was more than precious.

The chart from U73's log is from The Titanic Commutator (Vol.15;No.3;1991)  published by the Titanic Historical Society.

The Titanic Commutator (Vol.28;No.167;2004)